In a technical field such as expiration detection and breath alcohol detection in the past, there is a method of ionizing a target object and detecting the target object using a mass spectrometer operated in a vacuum.
For example, PTL 1 discloses a method of introducing microdroplets generated by an ionization method called an electrospray method into a second chamber in a vacuum, promoting desolvation through collision with gas introduced in the chamber, and introducing desolvated ions to mass spectrometer.
In the method, it is necessary to provide a vacuum pumping system for putting an analysis environment under a high vacuum in order to analyze generated ions. The method is based on the premise that a mass spectrometer operating under such a high vacuum is used.
On the other hand, as a technique not including the vacuum pumping system, PTL 2 discloses an ion detecting apparatus that introduces outside air such as breath alcohol into a housing, the inside of which is under atmospheric pressure, and, in order to provide a potential difference between a voltage-applied electrode and a detection electrode arranged in the housing, applies a direct-current voltage to the voltage-applied electrode to deflect charged particles included in the introduced outside air, and detects a part of the charged particles with a detection electrode.